Abstract : This paper deals with the City of Trenque Lauquen (located in the northwest of the Province of Buenos Aires, Argentina) as a case study; it attempts to understand processes of territorial transformation experienced since the city was founded in 1876. The "round lake", which gives its name to the city in the language of the Mapuche Indians, is surrounded by urbanization and located within the sub-humid Pampa. With a population of 30,764 in 2001, it concentrates the main regional economic activities: agriculture, dairy farming and cattle raising, together with secondary and tertiary activities